大家好，我的论文专案小组目前在使用Android Studio运行我们的android应用程序时遇到问题，概念是隐写术，我们正在使用https://github.com/guardianproject/PixelKnot/tree/version_2/PixelKnot/src/main/java/info/guardianproject/pixelknot的F5库
Here is our user interface and whenever clicking embed button, the app closes automatically
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.angel.filepicker, PID: 2972
java.lang.NullPointerException: Attempt to invoke virtual method 'void info.guardianproject.f5android.stego.StegoProcessor.addThread(info.guardianproject.f5android.stego.StegoProcessThread, boolean)' on a null object reference
at com.example.angel.filepicker.EmbedFragment$3.onClick(EmbedFragment.java:162)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
EmbedFragment.java代码
package com.example.angel.filepicker;
import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.MediaScannerConnection;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.Fragment;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import info.guardianproject.f5android.plugins.f5.Embed;
import info.guardianproject.f5android.stego.*;
import info.guardianproject.f5android.plugins.PluginNotificationListener;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import static android.app.Activity.RESULT_OK;
public class EmbedFragment extends Fragment {
private static final String TAG = "EMbed";
public EmbedFragment() {
}
private Activity a;
public File finalFile;
public File msgFile;
public byte[] seed = new String("This is hopefully Temporary").getBytes();
public String baseimage;
public String secret_file;
public Intent fileIntent;
public static Activity act;
public static Context cntx;
public StegoProcessor stego_processor;
//FOR FILE BUTTON
public static final int FILE_PICKER_REQUEST_CODE = 1;
Intent intent;
Button btn_choose_image;
ImageView image;
TextView text;
//FOR IMAGE BUTTON
File photoFile = null;
static final int CAPTURE_IMAGE_REQUEST = 2;
static final int SELECT_FILE = 3;
String mCurrentPhotoPath;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.embed_fragment, container, false);
cntx = getActivity().getBaseContext();
act = getActivity();
//initialize and set intent type
fileIntent = new Intent();
fileIntent.setType("*/*");
fileIntent.setAction(Intent.ACTION_GET_CONTENT);
text = view.findViewById(R.id.textView2);
//FOR FILE BUTTON
Button pickButton = view.findViewById(R.id.pick_from_activity);
pickButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// checkPermissionsAndOpenFilePicker();
startActivityForResult(Intent.createChooser(fileIntent, "Select File"), FILE_PICKER_REQUEST_CODE);
}
});
//FOR IMAGE BUTTON
btn_choose_image = view.findViewById(R.id.btn_choose_image);
image = view.findViewById(R.id.imageView2);
btn_choose_image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
captureImage();
}
});
final Button embedButton = (Button) view.findViewById(R.id.embedButton);
embedButton.setOnClickListener(embedButtonListener);
return view;
}
View.OnClickListener embedButtonListener = new View.OnClickListener() {
@Override
public void onClick(View view) {
if(baseimage !=null)
{
if ( secret_file != null) {
//ImageSteganography Object instantiation
Embed embed = new Embed(a,baseimage , secret_file, seed) {
@Override
public void run() {
super.run();
}
};
stego_processor.addThread(embed, true);
}
}
}
};
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// Log.e("onActivityResult", "requestCode " + requestCode + ", resultCode " + resultCode);
if (requestCode == FILE_PICKER_REQUEST_CODE && resultCode==RESULT_OK && data != null && data.getData() != null) {
Uri uri=data.getData();
try{
msgFile=new File(uri.getPath());//get the file
secret_file = uri.getPath();
//secretFile = getPathFromUri(getActivity(),uri);
Toast.makeText(act.getBaseContext(), "Picked file: " + msgFile, Toast.LENGTH_LONG).show();
//text.setText(textx);
}catch(Exception e){}
if(msgFile.length()==0){
try{
msgFile=new File(getPathFromUri(getActivity(),uri));//get the file
// secretFile = getPathFromUri(getActivity(),uri);
Toast.makeText(act.getBaseContext(), "Picked file: " + msgFile, Toast.LENGTH_LONG).show();
}catch(Exception e){
Log.e("Main","Unable to get file!");
e.printStackTrace();
}
}
}
if (requestCode == CAPTURE_IMAGE_REQUEST && resultCode == RESULT_OK) {
// baseImage = photoFile.getAbsoluteFile();
Bitmap myBitmap = BitmapFactory.decodeFile(photoFile.getAbsolutePath());
image.setImageBitmap(myBitmap);
}
//PROBLEMA NITO IS YUNG PAG DISPLAY NG PIC YUNG SIZE NG PIC .
// MAY METHOD NA RESIZIND PERO TSAKA NA CGURO PAG NALAGAY NA UI
if (requestCode == SELECT_FILE && data != null && data.getData() != null) {
// baseImage = getRealPathFromURI(getActivity(), data.getData());
Uri uri=data.getData();
try {
// mengambil gambar dari Gallery
Bitmap bitmap = MediaStore.Images.Media.getBitmap(getActivity().getContentResolver(), data.getData());
baseimage = uri.getPath();
image.setImageBitmap(bitmap);
text.setText(baseimage);
} catch (IOException e) {
e.printStackTrace();
}
}
}
// private String getRealPathFromURI(Context context, Uri contentUri) {
// Cursor cursor = null;
// try {
// String[] proj = { MediaStore.Images.Media.DATA };
// cursor = context.getContentResolver().query(contentUri, proj, null, null, null);
// int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
// cursor.moveToFirst();
// return cursor.getString(column_index);
// } catch (Exception e) {
// Log.e(TAG, "getRealPathFromURI Exception : " + e.toString());
// return "";
// } finally {
// if (cursor != null) {
// cursor.close();
// }
// }
// }
public static String getPathFromUri(final Context context, final Uri uri) {//get path name from a uri object(source: web)
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[] {
split[1]
};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
public static String getDataColumn(Context context, Uri uri, String selection,
String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = {
column
};
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is ExternalStorageProvider.
*/
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is Google Photos.
*/
public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}
//...................................................................................................................................
//FOR IMAGE BUTTON
private void captureImage() {
image.setImageResource(0);
final CharSequence[] items = {"Take Photo", "Choose from Library",
"Cancel"};
//ITO YUNG CHOICE KUNG TAKE PHOTO OR SELECT IMAGE . KAPAG TAKE PHOTO DAPAT
// NASASAVE SA GALLERY PERO WALA AKO NAKITA SA GALLERY KO HAHAH FEELING KO MAS OKAY PAG DI NLNG NASSASAVE
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Add Photo!");
builder.setIcon(R.mipmap.ic_launcher);
builder.setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int item) {
if (items[item].equals("Take Photo")) {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureIntent.resolveActivity(getContext().getPackageManager()) != null) {
// Create the File where the photo should go
try {
photoFile = createImageFile();
displayMessage(getActivity().getBaseContext(), photoFile.getAbsolutePath());
Log.i("Stegrapp", photoFile.getAbsolutePath());
// Continue only if the File was successfully created
if (photoFile != null) {
Uri photoURI = FileProvider.getUriForFile(getActivity(),
"com.example.angel.filepicker.fileprovider",
photoFile);
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
startActivityForResult(takePictureIntent, CAPTURE_IMAGE_REQUEST);
}
} catch (Exception ex) {
// Error occurred while creating the File
displayMessage(getActivity().getBaseContext(), ex.getMessage().toString());
}
} else {
displayMessage(getActivity().getBaseContext(), "Nullll");
}
//PROBLEMA NITO IS YUNG PAG DISPLAY NG PIC YUNG SIZE NG PIC .
// MAY METHOD NA RESIZIND PERO TSAKA NA CGURO PAG NALAGAY NA UI
} else if (items[item].equals("Choose from Library")) {
intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"), SELECT_FILE);
} else if (items[item].equals("Cancel")) {
dialog.dismiss();
}
}
});
builder.show();
}
//........................................................................................................
//ITO YUNG PAG CREATE NG FILE NUNG IMAGE GALING CAMERA
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = getContext().getExternalFilesDir(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = image.getAbsolutePath();
return image;
}
private void displayMessage(Context context, String message)
{
Toast.makeText(context,message,Toast.LENGTH_LONG).show();
}
public static void show(final String toast){
act.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(EmbedFragment.cntx,toast,Toast.LENGTH_LONG).show();
}
});
}
}
MainActivity.java代码
package com.example.angel.filepicker;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
private static int SPLASH_TIME_OUT = 4000;
ImageView imageView;
Toolbar toolbar;
ViewPager viewPager;
TabLayout tabLayout;
FloatingActionButton shareButton;
Button btn_choose_image;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = findViewById(R.id.toolbar_id);
viewPager = findViewById(R.id.viewPager_id);
tabLayout = findViewById(R.id.tabLayout_id);
shareButton = findViewById(R.id.shareButton_id);
//sharing
shareButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent myIntent = new Intent(Intent.ACTION_SEND);
// this should be the file
// must create folder the carrier image
// this is a sample that takes string
//intent takes string should be file
myIntent.setType("text/plain");
//should be the carrier image
String shareBody = "Your body here";
// can be removed / optional
String shareSub = "Your subject here";
myIntent.putExtra(Intent.EXTRA_SUBJECT,shareSub);
myIntent.putExtra(Intent.EXTRA_TEXT,shareBody);
startActivity(Intent.createChooser(myIntent, "Share using"));
}
});
// SETTING UP ViewPagerAdapter
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
viewPagerAdapter.addElements(new EmbedFragment(), "Embed");
viewPagerAdapter.addElements(new ExtractFragment(), "Extract");
viewPager.setAdapter(viewPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
}
}